1. Field of the Invention
This invention relates to novel fire-resistant polyimides and copolyimides prepared from 1-[(diorganooxyphosphonyl)methyl]-2,4- and -2,6-diaminobenzenes. More particularly, it relates to phosphorus-containing polyimides prepared by a two-stage polycondensation reaction of 1-[(diorganooxyphosphonyl)methyl]-2,4- and -2,6-diaminobenzenes with a tetracarboxylic dianhydride, such as pyromellitic dianhydride and benzophenone tetracarboxylic dianhydride. In addition, it relates to phosphorus-containing copolyimides prepared by reacting 1-[(diorganooxyphosphonyl)methyl]-2,4- and -2,6-diaminobenzenes and a common diamine, such as m-phenylenediamine, with a tetracarboxylic dianhydride.